The backplate makes big difference when adding a waterblock or after-market cooler. My 4890 (no backplate) always had a curve to it after I added a waterblock, my 6950 (with backplate) has no such curve and the waterblock on it is heaver and the card is longer. Even my 2900XT (with backplate) didn't curve with a waterblock. If you are running stock then it makes only a aesthetic effect but if you want a heavy after-market cooling option then it makes a big difference.